<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>进度条</title>
		<style type="text/css">
			.bar {
				width: 500px;
				height: 30px;
				border: 2px solid red;
				border-radius: 16px;
				padding: 1px;
			}

			.bar-in {
				width: 50%;
				height: 100%;
				background-color: red;
				border-radius: 16px;
				transition: all .7s;
			}

			.bar:hover .bar-in {
				width: 100%;
			}
		</style>
	</head>
	<body>
		<div class="bar">
			<div class="bar-in"></div>
		</div>
	</body>
</html>
